The proposed research is planned within two main categories. The first will continue a detailed analysis of the effects of hippocampal damage in older juvenile rhesus macaques and the second is concerned with the effect of equivalent lesions as a function of age. Experiments in the first category attempt to 1. determine the extent of functional relationship between the hippocampus and the inferotemporal cortex: the effects of hippocampal and inferotemporal lesions will be compared on a battery of tests sensitive to hippocampal damage in both the visual and tactual modes. Special attention will be paid to the possible role of the hippocampus in transmodal memory. 2. Identify possible motivational post-operative changes after hippocampal damage such as stimulus satiation. In the second category, we intend to continue our investigations of the effects of early fornix and hippocampal damage on spatial and object reversal tasks and retention tasks. The current year will see re-testing of infants at two years of age.